ObjectiveTo investigate the epidemiological characteristics of human brucellosis (hereinafter referred to as brucellosis) in Baoshan City, Yunnan Province, and to provide scientific evidence for adjusting prevention and control strategies. MethodsBased on the surveillance data of reported brucellosis cases in Baoshan City from 2020 to 2023 and the information collected through individual epidemiological questionnaire surveys, the epidemic status and clinical characteristics of brucellosis in Baoshan City were analyzed using descriptive epidemiological methods. ResultsA total of 85 brucellosis cases were reported in Baoshan City from 2020 to 2023, and detailed individual information was obtained for 83 of them. Brucellosis in Baoshan City showed a clear seasonal pattern, with peak incidence from May to September. The average annual incidence rate was 0.80/100 000, with a male-to-female ratio of 7.5∶1. And 82.35% of the cases aged 30 to 60 years, with farmers being the predominant affected group. The main clinical manifestations of the cases were myalgia and arthralgia. Regarding transmission routes, 87.95% of the cases had a contact history with cattle, with livestock rearing and grazing being the main exposure modes. Most infections occurred at home. ConclusionFrom 2020 to 2023, the incidence of brucellosis in Baoshan City exhibited a fluctuating upward trend, with a peak period from May to September. Males and farmers were identified as the primary affected populations. It is recommended to strengthen livestock surveillance and control, and to enhance both awareness and self-protection capacity among high-risk groups.

Objective:To analyze the morphology and molecular biology of Rhodococcus erythropolis isolated from blood culture, and clarify its microbiological characteristics, clinical diagnosis and treatment. Methods:Strain F1069 was isolated and cultured. Then, it was analyzed by morphology, physiological tests, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS), 16S rRNA gene sequencing, and whole-genome sequencing analysis.Results:The colonies of Rhodococcus erythropolis were light yellow, moist, round, and raised, and had neatly-edged margins after being cultured for 48 h. They could turn orange-red after a prolonged cultivation time. The strain was gram-positive bacillus without spores and was negative in acid-fast staining. The strain was identified as Rhodococcus erythropolis by MALDI-TOF MS, and the result was confirmed by 16S rRNA gene sequencing. The F1069 strain contained the RbpA resistance gene and multiple virulence genes. Conclusions:Cases of Rhodococcus erythropolis infection are rare. The diagnosis of such cases depends on the pathogen detection results, especially molecular biology methods. A definitive diagnosis enables rapid guidance for clinical anti-infection treatment.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To observe the effect of human umbilical cord mesenchymal stem cell-derived exo-somes(HUC-MSC-Exo)on microglial polarization in neonatal rats with white matter injury(WMI).Methods Three-day-old Sprague-Dawley rats were randomly divided into sham group(Sham),hypoxia-ischemia group(HI)and HUC-MSC-Exo group,with 12 rats in each group.Unilateral common carotid artery ligation combined with hy-poxia(8％oxygen and 92％nitrogen)was used to construct a WMI rat model.Exosomes were extracted by ultra-high-speed centrifugation and characterized by nanoflow cytometry,western blot experiments and transmission electron mi-croscopy.Brain stereotaxic-assisted inferior ventricular transplantation exo(2×108 particles/μL)was performed and brain tissue samples were collected 14 days after HI.Hematoxylin-eosin(HE)staining was used to observe morpho-logical changes of brain tissue.Nissl staining was used to observe Nissl body formation in brain tissue;Luxol fast blue(LFB)staining was used to observe the formation of myelin sheath in brain tissue.Immunofluorescence staining was used to observe the localized expression of ionic calcium binds adaptor molecule 1(Iba1).The protein expres-sion levels of cluster of differentiation 86(CD86),inducible nitric oxide synthase(iNOS),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),CD206,arginase-1(Arg-1),IL-10 and transforming growth factor-β(TGF-β)were detected by western blot.Results The results of nanoflow cytometry,western blot and transmission electron microscopy showed that the diameter of HUC-MSC-Exo particles was between 30 and 150 nm,and the oval-like shape and membrane-like structure were visible,and the exo markers CD9,CD63 and TSG101 were positive,while calnexin was negative.HE staining,Nissl staining and LFB staining showed that compared with the Sham group,the HI group had brain tissue structure destruction,which was manifested by cell morphological changes,nerve fiber ar-rangement disorder and vacuolation,Nissl body dissolution or even disappearance,and myelination was blocked.HUC-MSC-Exo significantly reversed the pathological changes in the HI group.The results of immunofluorescence staining and western blot showed that the microglial marker Iba1 was mainly expressed in the subventricular zone(SVZ),and the expression of Iba1 protein in the SVZ region increased after HI compared with the Sham group(t=15.95、20.31,P<0.01).HUC-MSC-Exo significantly reduced the expression of Iba1 protein in the HI group(t=10.35、11.01,P<0.01).The results of western blot showed that the expressions of M1 microglia markers(CD86 and iNOS)and pro-inflammatory cytokines(TNF-α and IL-1β)were significantly increased after HI(t=10.98、7.68、15.13、13.13,both P<0.01),and the expressions of M2 microglia markers(CD206 and Arg-1)and anti-inflammatory cytokines(IL-10 and TGF-β)were also increased after HI(t=14.26、9.38、8.82、7.42,both P<0.01).HUC-MSC-Exo decreased the protein expression of CD86,iNOS,TNF-α and IL-1β(t=9.79、5.81、8.06、7.03,all P<0.01)and increased the protein expression levels of CD206,Arg-1,IL-10 and TGF-β compared to the HI group(t=12.90、8.16、8.98、9.49,both P<0.01).Conclusion HUC-MSC-Exo attenuates WMI in neonatal rats by regulating microglial polarization.

Objective To observe the effect of human umbilical cord mesenchymal stem cell-derived exo-somes(HUC-MSC-Exo)on microglial polarization in neonatal rats with white matter injury(WMI).Methods Three-day-old Sprague-Dawley rats were randomly divided into sham group(Sham),hypoxia-ischemia group(HI)and HUC-MSC-Exo group,with 12 rats in each group.Unilateral common carotid artery ligation combined with hy-poxia(8％oxygen and 92％nitrogen)was used to construct a WMI rat model.Exosomes were extracted by ultra-high-speed centrifugation and characterized by nanoflow cytometry,western blot experiments and transmission electron mi-croscopy.Brain stereotaxic-assisted inferior ventricular transplantation exo(2×108 particles/μL)was performed and brain tissue samples were collected 14 days after HI.Hematoxylin-eosin(HE)staining was used to observe morpho-logical changes of brain tissue.Nissl staining was used to observe Nissl body formation in brain tissue;Luxol fast blue(LFB)staining was used to observe the formation of myelin sheath in brain tissue.Immunofluorescence staining was used to observe the localized expression of ionic calcium binds adaptor molecule 1(Iba1).The protein expres-sion levels of cluster of differentiation 86(CD86),inducible nitric oxide synthase(iNOS),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),CD206,arginase-1(Arg-1),IL-10 and transforming growth factor-β(TGF-β)were detected by western blot.Results The results of nanoflow cytometry,western blot and transmission electron microscopy showed that the diameter of HUC-MSC-Exo particles was between 30 and 150 nm,and the oval-like shape and membrane-like structure were visible,and the exo markers CD9,CD63 and TSG101 were positive,while calnexin was negative.HE staining,Nissl staining and LFB staining showed that compared with the Sham group,the HI group had brain tissue structure destruction,which was manifested by cell morphological changes,nerve fiber ar-rangement disorder and vacuolation,Nissl body dissolution or even disappearance,and myelination was blocked.HUC-MSC-Exo significantly reversed the pathological changes in the HI group.The results of immunofluorescence staining and western blot showed that the microglial marker Iba1 was mainly expressed in the subventricular zone(SVZ),and the expression of Iba1 protein in the SVZ region increased after HI compared with the Sham group(t=15.95、20.31,P<0.01).HUC-MSC-Exo significantly reduced the expression of Iba1 protein in the HI group(t=10.35、11.01,P<0.01).The results of western blot showed that the expressions of M1 microglia markers(CD86 and iNOS)and pro-inflammatory cytokines(TNF-α and IL-1β)were significantly increased after HI(t=10.98、7.68、15.13、13.13,both P<0.01),and the expressions of M2 microglia markers(CD206 and Arg-1)and anti-inflammatory cytokines(IL-10 and TGF-β)were also increased after HI(t=14.26、9.38、8.82、7.42,both P<0.01).HUC-MSC-Exo decreased the protein expression of CD86,iNOS,TNF-α and IL-1β(t=9.79、5.81、8.06、7.03,all P<0.01)and increased the protein expression levels of CD206,Arg-1,IL-10 and TGF-β compared to the HI group(t=12.90、8.16、8.98、9.49,both P<0.01).Conclusion HUC-MSC-Exo attenuates WMI in neonatal rats by regulating microglial polarization.

Purpose To explore the clinicopathological features,diagnosis and differential diagnosis of mantle cell lymphoma(MCL)with aberrant expression of CD10.Methods 14 cases of MCL with aberrant expression of CD10 were analyzed using hematoxylin-eosin,immunohistochemical stains,in situ hybridization,and fluorescence in situ hy-bridization(FISH)techniques to observe the histological morphology,immunophenotype,and molecular genetic char-acteristics.The relevant literatures were reviewed.Results There were 11 males and 3 females,with a male-to-fe-male ratio of 11∶3.The age ranged from 49 to 80 years,with an average age of 64.4 years and a median age of 64 years.10 cases occurred in lymph nodes,1 case in the nasopharynx,1 case in the right colon,1 case in the right eye-lid,and 1 case in the right testis.According to the Ann Arbor staging system,8 cases were classified as stage Ⅳ and 5 cases as stage Ⅲ,and 1 case with undetermined staging.Histologically,there was diffuse effacement of the normal architecture by tumor cells infiltration.Transparent degenerate small blood vessels and scattered individual epithelial-like tissue cells could be observed in the background.Among them,8 cases(8/14,57.14％)were composed of uni-form small to medium-sized lymphocytes with slightly irregular nuclei,unevenly dispersed chromatin,inconspicuous nucleoli,and scant cytoplasm,along with observable mitotic figures.In 3 cases(3/14,21.43％),the tumor cells were large and markedly pleomorphic,with round or irregular nuclei,prominent nucleoli,frequent mitotic figures,and abundant pale cytoplasm.Tumor cells in 3 cases(3/14,21.43％)were resembling lymphoblasts,characterized by round nuclei,fine chromatin,inconspicuous nucleoli,frequent mitotic figures,and scant cytoplasm.Immunophenotyp-ically,CD21 staining showed residual follicular dendritic meshworks.The tumor cells were diffusely and strongly posi-tive for CD20(14/14),PAX5(7/7),CD5(14/14),Cyclin D1(14/14),SOX11(11/11),and BCL2(13/13),partially positive for BCL6(8/14,57.14％)and MUM1(6/9,66.67％),but negative for CD3(14/14)and CD23(14/14).Among 14 cases,10 cases were diffusely and strongly positive for CD10(10/14,71.43％),and 4 cases were partially positive for CD10(4/14,28.57％).The percentage of Ki67 index ranged from 10％to 90％.All cases were negative for EBER(8/8).FISH analysis was performed in 9 cases,among which 7 cases showed CCND1 gene rearrangement,another 2 cases failed to detect due to insufficient tissue samples.Bone marrow biopsy was performed in 13 cases,revealing involvement in 8 cases(8/13,61.54％)and no involvement in 5 cases(5/13,38.46％).Con-clusion MCL with aberrant expression of CD10 is very rare,which commonly exhibits a diffuse growth pattern and blastoid and pleomorphic variants.It often has a high Ki67 proliferation index and poorer prognosis,and should be dis-tinguished from other subtypes of CD1O-positive B-cell lymphomas.

The purpose of this study was to prepare high affinity monoclonal antibodies(mAbs)a-gainst bovine viral diarrhea virus(BVDV)and establish a double antibody sandwich ELISA detec-tion method.BVDV was purified by differential ultracentrifugation and used to immunize BALB/c mice.Hybridoma cells were prepared by fusing spleen cells from the immunized mice with SP2/0 cells.Positive cells were screened by indirect ELISA.A double-antibody sandwich ELISA method for detecting BVDV was developed using monoclonal antibody 4D11 as the capture antibody and HRP-labeled monoclonal antibody 3F3 as the detection antibody.The results of the ELISA and the determination of the variable region gene sequence of monoclonal antibodies indicated that the two monoclonal antibodies recognize different antigenic epitopes.Specificity tests showed that two monoclonal antibodies specifically recognize BVDV and did not cross-react with other bovine viru-ses associated with diarrhea.Indirect immunofluorescence assay and Western blot assay demonstra-ted that both mAbs exhibited strong reactivity with BVDV.The double antibody sandwich ELISA detection method established in this study had good specificity.The sensitivity test revealed that the method could detect a minimum virus amount of 3.1 × 104 TCID50.The reproducibility test showed that the inter-batch coefficient of variation(Cv)was between 2.47％and 7.44％,and the intra-batch Cv was between 1.71％and 9.89％,indicating good reproducibility.The establishment of this method provides an effective technical tool for the rapid diagnosis and prevention and con-trol of BVDV.